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Hello everyone,
I need to put a railing onto my stairs going to the second level in my garage. I'm having some trouble finding information for the best way to attach the post at the bottom of the stairs to the stringer. Should I use bolts or lag screws and if so what size is best?
Thank you,
Steve,
There are several ways to mount newel posts, you can buy different kits from stair parts manufacturers. How you mount the newel post can often depend on the layout
of the stairs, and the structure of the house around the stairs. I would see if I can get a copy of L.J. Smiths balustrade installation guide, it is on their website and has a lot of
information that will help you decide how you want to install your post.
Tom
You should be able to find what you need here: https://www.ljsmith.com/install
John
I am helping my son with his exterior stairs. He has a long run of 4' wide stairs with 4 stringers from a deck down to the lawn. We cut them at the halfway point, picked up the lower section with his Kubots and set them down. Made a new 4' x 8' landing , cut a few treads off the lower portion to fit the new grade and reinstalled the bottom section 180 degrees from original so the stairs now end up almost under the deck. 4" x 4" treated posts lagged into the stringers with 3/8" x 5" Spax Powerlags, two per post. BTW, the contractor (less than 2 years ago) just banged a lot of the work together with non-galvanized nails with a nail gun. Terribly rusted already from the corrosive pressure treatment chemicals. Most of it was to temporarily hold it in place until they used non-corrosive fasteners. Good lesson though. Even yellow zinc chromate isn't going to hold up. Hot dip galvanized or special approved fastener coatings are needed with PT lumber.
https://images.homedepot-static.com/...compressed.jpg
There are a lot of ways to skin this cat. Without knowing exactly what your dealing with it’s hard to recommend a specific attachment method. A few pictures of the desired location of the newel post and any pictures of the structure of the stair assembly would be helpful to give specific recommendations.
However, as a generality, if you are going to attach directly to the stringer, and you still have access to the stringers, I’d suggest securely fastening blocking, with screws and glue, between the bottom stringers to stiffen the assembly up and to give a solid structure for the entirety of the threaded portion of any lags used to bite into. It’s really quite amazing how much leverage you can exert on a newel post when applying force near the top. If you want something that’s rock solid and holds up over time, it’s worth spending some time getting it right now.
I’m not a professional stair builder (so YMMV), but I have worked enough remodeling jobs that needed newel repairs to know that many newel posts are inadequately attached.
I think the strongest method, and the least likely to have catastrophic failure, is all thread through the middle of the newel post. That is the reason for the big cap/ball on top of a newel post. It is a cork to cover the hole that can be pulled to retighten the nut as needed. I would build up the post from two or more pieces of wood and leave a channel in the middle,. Much easier then drilling a one piece post.
Bil lD
If you can locate a lag bolt where it will not show, like through the stringer into the post, I would use a couple and some glue. Usually you can only secure the post at the bottom and a little when you attach the handrail. The height of the post produces 3 feet or so of leverage on the attachment. So it's good to use fairly large fasteners where you can, 1/4 or 5/16 lags. On the other hand, where this isn't possible, even a few trim head screws from the outside into the stringer will be fairly strong and may not fail. (I've only made one nice interior staircase so I am not an expert - I used both a lag and some trim head screws).
Here's a video showing what appears to be a very sturdy way to mount a newel post. I think this is what Bill is saying but I learn better by seeing.
https://www.youtube.com/watch?v=hOaGlDACXLI
If you can get inside the stringer I would pick up a Simpson plate of some description or a piece of scrap and through-bolt the bottom of the post. Counter sink and plug the bolts if aesthetics are in play. Newel posts take a heck of a beating and it is nice when they stay put. If you can, dado the stringer for better locking.
An important point is that regardless of method there needs to be an easy way to access the hardware and tighten it up from time to time. As wood drys and stresses build up the hardware will get loose.
Bill D